Refractory composition for hot tops



Patented June 18, 1929.

UNITED STATES EUGENE L. MESSLER, OI PITTSBURGH, PENNSYLVANIA.

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No Drawing. Original application filed December 8, 1926, Serial No. 153,250. Divided and this application filed September 17, 1927. Serial No. 220,288.

This invention relates to a composition for use in the manufacture of hot tops for ingot molds and the like, and constitutes a division of copending application Serial No. 153,250, filed December 8, 1926.

As is well known in the art, feeders or hot tops are manufactured of clay or some other more or less refractory composition, and: are placed on the ingot mold prior to the operation of teeming or pouring the ingot. These hot tops are used not only as a receptacle for the sink head of the ingot, but also serve to keep the metal in a fluid condition during pouring, so that it will feed properly into 5 the mold.

Certain problems are encountered in the manufacture and use of hot to s. One such problem is caused by the fragillty of the material of which hot tops have been made,

which is apt to lead to their breakage in shipment. Another problem is that most hot tops during a preheating operation, or when they, come into contact wlth metal during pouring are apt to crumble, slag, crack, or

spall. These-actions are a t to result in the inclusion of articles of t e hot top in the ingot. Anot er problem is due to the fact that a hot top during pouring may slag sufiieiently to become attached to the sink head;

this possibility necessitating that a hot top be blocked up on the ingot mold, so that the blocking maybe removed after thein ot has 'been teemed to permit the; top to sett e with the steel as it contracts.

As stated above, the-general function of a hot top is to provide a good insulating reservoir to retain the heat of the metal, so that it will fit well into the mold. Previously a thoroughly successful material for hot tops 40 had not been evolved. If a hot top be of too dense a material, such as plastic clay, such material will be too good a conductor of heat to rmit the hot top to perform its function satisfactorily. It is also sodense that it will crack and spall badly giving brick inclusions in the steel. If, on the contrary, the hot to be made of relatively porous material suc as slag, this material 15 not sufliciently bonded to prevent the scaling of! of particles from the body of the hot top.

The object of the present invention is to provide a composition for the manufacture of hot tops of such nature that the hot tops made thereofwill not be readily broken during shipment, or when placed 1n 'posltion on the ingot mold; and which gives the hot top hlgh insulating qualities, without crumbling,

'slagging, or cracking, or spalling when su jected to applied heat or to .contact with the molten metal.

A top top made of the special composition of the present invention has the advantages of a relativel high'fusing point, relatively low conductlvity of. "heat, and sufiicient strength to avoid breakage of the hot top dur- 1ng shipment and use. Such desirable composition comprises flint clay, grog (granulated or powdered brick) and plast1c clay. The proportions of these ingredients may be varied within fairly wide limits in accordance with the temperature to which thehot top is to be subjected, and in accordance with the probable shocks which it must withstand during shipment and use. A desirable composition may be secured by utilizing the grog in the proportion of 10% to 20% of the total composition, flint clay in the proportion of 40% to of the total composition and plastic clay as the remaining ingredient. A composition comprising the constituents in such proportions as to be applicable to a wide eneral use comprises 10% of grog, 45% of int clay, and'45% of plastic clay.

In the refractory trade the term flint clay is used to describe a hard, rocklike material which, when ground and mixed with water ossesses low bonding properties. The term plastic, soft, or bonding clay is taken to mean a clay which, when groundand mixed with water, has high bonding properties. The term grog 1s taken to mean fire clay, which has been burned at a hignh temperature and round.

addition to the fact that it serves as a satisfactory heat insulator, a hot to made of this com ,osition has higher re ractory qualities an greater toughness than where plastic clay is'the sole ingredient. Hot tops made of such composition do not in general suffer deterioration from breakage in shipping, or from spalling of the hot top before or uring a pouring operation.

In practice hot tops made of plastic cla frequently crack in all directions, in sue manner as to form a net work of cracks running into each other. Hot tops made of slag frequently crumble, or elsefuse under the hot temperature of the molten metal. In either case some of the material of the hot top is included in the ingot, and may work down 110 wardly through the plastic metal of the ingot to a point below the sink head. This obviously has a highly deleterious effect on the metallic composition of the ingot.

When a hot top formed of the composition described herein does crack, such cracking is along a few well defined vertical lines, so that there is no danger that portions of the hot top may break off and be included in the metal of the ingot.

Hot tops so constructed do not fuse under the temperatures attendant upon teeming an ingot, and consequently none of the material of the hot top flows and is mixed with the metal of the ingot.

The composition of the present invention may also be used for the plugs used to close the openings in ingot molds which receive the stripping plugs.

What I claim is:

1. A composition for ingot mold hot tops and plugs comprising flint clay in the relative proportion of forty per cent to sixty per cent, grog in the relative proportion of ten per cent to twenty per cent, and plastic clay.

2. A composition for ingot mold hot tops and plugs comprising flint clay in the approximate proportion of forty-five per cent, grog in the approximate proportion of ten per cent, and plastic clay.

In witness whereof, I hereunto sct my hand.

EUGENE L. MESSLER. 

